So, I looked up various methods to work this technique and used Ysolda's, because it's very simple:
I just love the way this edge looks, as if the knitting has started in the middle. It also stops that flare out perfectly. The odd thing is after I finished the hat, I have spotting a number of time, in my knitting, I have used it - recently on this Buchaille Hat and as far back as Endpaper Mitts, in 2011. It's like I have to keep rediscovering this awesome cast on every year or so.
I also used it on the matching mitts, and used the matching cast off to finish them.
Because yes, I got the mitts finished. It's a great set. I'm about to block it, and will get some photos in the wild when we go camping next weekend.